/*
 * Copyright (c) 2013, 2025, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package jdk.jfr.event.os;

import java.util.List;

import jdk.jfr.Recording;
import jdk.jfr.consumer.RecordedEvent;
import jdk.test.lib.jfr.EventNames;
import jdk.test.lib.jfr.Events;
import jdk.test.lib.Platform;

/**
 * @test
 * @requires vm.flagless
 * @requires vm.hasJFR
 * @library /test/lib
 * @run main/othervm jdk.jfr.event.os.TestThreadContextSwitches
 */
public class TestThreadContextSwitches {
    private final static String EVENT_NAME = EventNames.ThreadContextSwitchRate;

    public static void main(String[] args) throws Throwable {
        while (true) {
            try (Recording recording = new Recording()) {
                recording.enable(EVENT_NAME);
                recording.start();
                recording.stop();
                List<RecordedEvent> events = Events.fromRecording(recording);
                if (!events.isEmpty()) {
                    for (RecordedEvent event : events) {
                        System.out.println("Event: " + event);
                        Events.assertField(event, "switchRate").atLeast(0.0f);
                    }
                    return;
                }
                // Thread context switch rate is unreliable on Windows because
                // the way processes are identified with performance counters.
                if (!Platform.isWindows()) {
                    Events.hasEvents(events);
                }
            }
        }
    }
}
